Paitishahem

Paitishahem (Patishahya; Feast of Bringing in the Harvest)

January, February, September; 26th-30th days of Shahrewar, the sixth Zoroastrian month
Paitishahem is the third of the six great seasonal feasts, known as gahambars, of the Zoroastrian religion. Each of the six gahambars correlated with a phase of agricultural production—in this case, bringing in the harvest—and honored one of the six things created by God: sky, water, earth, plants, animals, and humankind.
Traditionally, the gahambars were joyous festivals that lasted five days and provided farm workers with a much-needed respite from their labors. The first four days were spent in preparation for the feasting that took place on the fifth day. Today, however, so many Zoroastrians live in urban areas that the importance of the gahambars has diminished somewhat.
The Zoroastrian calendar has 12 months of 30 days each, plus five extra days at the end of the year. Because of discrepancies in the calendars used by widely separated Zoroastrian communities around the world, there are now three different calendars in use, and Paitishahem can fall either in January, February, or September according to the Gregorian calendar.
There are only about 100,000 followers of Zoroaster (also known as Zarathushtra, believed to have lived around 1200 b.c.e.) today, and most of them live in northwestern India or Iran. Smaller communities exist in Pakistan, Sri Lanka, Canada, the U.S., England, and Australia.
SOURCES:
RelHolCal-2004, p. 67